“It is not surprising that San Diego ranks so high on the lists with El Camino Real in the Del Mar Heights submarket leading the way,” said Jones Lang Executive Vice President Bess Wakeman.

She said the freeway-close street commands top rents because it’s near premier executive housing and highly ranked schools.

“While rental rates may be high, the above-market parking ratios complement the unreserved parking charges that remain, for the time being, free,” Wakeman added.

Jones Lang said the Del Mar Heights area originally appealed to law firms and financial services but lately has attracted medical device companies, health care technology firms and online gaming developers.

For central business districts, San Diego’s top street proved a bit trickier to pinpoint. Jones Lang ranked 10th Avenue at No. 1 because its one office building, DiamondView Tower, posts the highest asking rents, averaging $3.10 per square foot per month.

Jones Lang issued rankings on 20 streets in both central business districts and suburban markets. Besides San Diego, other streets in California on the list were in the San Francisco Bay Area, Los Angeles, Oakland and Orange County.

David Marino, specializing in suburban properties at the Hughes Marino brokerage, said the research may be technically correct, but he questioned its utility. It’s based on asking, not effective rents, he said, and does not distinguish between the most recent rent deals and the average over time. He also said it is “silly” to rank downtown’s top street based on one building.

The more general trend, however, is nothing new, he said.

“You can look from the mid-1990s on to today, and Del Mar Heights and UTC (University Towne Centre area) generally have been more expensive than downtown,” he said. Mission Valley rents also outrank downtown.

Downtown continues to suffer from high vacancy rates and thus lower rents left over from overbuilding 25 years ago, Marino explained, while vacancies are lower in other key markets and thus command higher rents.